The mechanical-type cam chain tensioner for the above models was changed in 2008. The tensioner was improved to reduce the possibility of insufficient cam chain tension and the resulting engine damage that could be caused by a loose cam chain. All 2008 and newer models have the new tensioner.
Inspection / Diagnosis
The symptom of loose cam chain tension is excessive rattle noise near the cam chain tensioner while the engine is running.
The damage caused by a loose cam chain tension could be engine damage due to valve/piston contact or severe wear of the cam chain drive gear on the crankshaft.
If any of the above symptoms or damage occurs, make sure the cam chain tensioner assembly is replaced with a new tensioner.
NOTE: The original failed tensioner may function properly when removed and bench tested. If the original tensioner is reinstalled, it will likely fail again causing repeat engine noise or damage.